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PubMedDate not supplied

Lung mineral fibers of former miners and millers from Thetford-Mines and asbestos regions: a comparative study of fiber concentration and dimension.

Fiber dimension and concentration may vary substantially between two necropsy populations of former chrysotile miners and millers of Thetford-Mines and Asbestos regions. This possibility could explain, at least in part, the higher incidence of respiratory diseases among workers from Thetford-Mines than among workers from the Asbestos region. The authors used a transmission electron microscope, equipped with an x-ray energy-dispersive spectrometer, to analyze lung mineral fibers of 86 subjects from the two mining regions and to classify fiber sizes into three categories. The most consistent difference was the higher concentration of tremolite in lung tissues of workers from Thetford-Mines, compared with workers from the Asbestos region. Amosite and crocidolite were also detected in lung tissues of several workers from the Asbestos region. No consistent and biologically important difference was found for fiber dimension; therefore, fiber dimension does not seem to be a factor that accounts for the difference in incidence of respiratory diseases between the two groups. The greater incidence of respiratory diseases among workers of Thetford-Mines can be explained by the fact that they had greater exposure to fibers than did workers at the Asbestos region. Among the mineral fibers studied, retention of tremolite fibers was most apparent.

Aged↗
PubMedDate not supplied

Does coal mine dust present a risk for lung cancer? A case-control study of U.S. coal miners.

This paper evaluates the relationship between the risk of lung cancer mortality and coal mine dust exposure under control by cigarette smoking status. Two case-control studies based on 317 white male lung cancer mortality cases are presented. A one-to-one matched-case design allows examination of the risk of coal mine dust exposure and cigarette smoking. A two-to-one matched-case design was employed to examine the lung cancer risk of coal mine dust exposure independent of cigarette smoking. Based upon these data, no evidence of a coal mine dust exposure-lung cancer risk was found, although the expected increased risk for lung cancer in cigarette smokers was observed. There was no evidence of an interactive effect between cigarette smoking and coal mine dust exposure.

Coal Mining↗
PubMedDate not supplied

Dust exposures at U.S. surface coal mines in 1982-1983.

Exposures to British Mining Research Establishment corrected respirable dust and respirable quartz at U.S. surface coal mines during 1982-1983 were evaluated from coal mine operator and Mine Safety and Health Administration (MSHA) inspector samples. The average respirable quartz concentration from inspector samples ranged from .34-.49 mg/m3 for drilling jobs and .18 mg/m3 for bulldozer operators. For most other surface coal mine jobs, the average respirable quartz concentration was less than .1 mg/m3, and the average respirable dust concentration was less than 2 mg/m3. The results from the analysis of quartz exposures are consistent with epidemiological results for an increased silicosis risk among drillers. It is unclear, however, whether the MSHA samples provide a representative estimate of the average annual quartz concentration for drillers. Results suggest the need for a greater number of quartz samples to be taken on strip coal miners, particularly on drillers and bulldozer operators.

Air Pollutants, Occupational↗
PubMed2002

Food chain transfer of zinc within the ecosystems of old and modern metalliferous mine wastes.

Concentrations of zinc in mine waste, vegetation, invertebrate and small mammals from abandoned mines and a modern mine site have been determined in order to assess and compare environmental risk. Very high concentrations of zinc in mine waste from all sites were reflected in vegetation zinc levels but not in invertebrates and mammals. Physiological regulatory control mechanisms operate to optimise zinc retention, and maintain homeostasis in animals by enhancing absorption of zinc from diets low in the trace element, and by buffering the potential accumulative effects of high dietary levels of the metal. Zinc is not considered to be an acute toxicity factor precluding colonisation of these mine sites by invertebrates and mammals though it maybe a selective force influencing the species composition and relative abundance in animal communities.

Animals↗
PubMed2004

[Impact of acid mining drainage on the quality of superficial waters and sediments in the Marrakesh region, Morocco].

The aim of the present study is the evaluation of the effects of the acid drainage of three abandoned mining sites: SB-Othmane, Kettara and Draâ-sfar, on water and sediment quality of the Tensift River and its two temporary tributaries, the Kettara and El-Coudia Oueds. These mining sites located near Marrakesh contain mining residues abandoned for ten to twenty years. They are presently in an agricultural region of the Haouz district. In each site, these uncontrolled mining residues present a high level of metallic sulphide and generate, during rainy periods, leaching products which have physical and chemical characteristics of acid mine drainage (AMD). These percolates display an acidic pH ranging from 2.5 to 5.2, a high electric conductivity, large amounts of sulphate and heavy metals, especially under dissolved form (e.g. Cd: 17.34 mg l(-1); Fe: 1734 mg l(-1); Zn: 3935 mg l(-1)). Except for Pb, the free ionic form is the most abundant metallic form, as showed by calculations using the speciation GEOCHEM program. The analysis of water and sediments of the surrounding superficial aquatic ecosystems shows a modification of water chemical facies and an enrichment in heavy metals, mainly under the solid phase for Fe, Pb, Cu, Co, Cr and Ni, and under dissolved fraction for Cd and Zn. The dissolved fraction of these metals is dominated by the free ionic form, considered as available for organisms. Furthermore, sediments contain important quantities of heavy metals (Pb: 1450 microg g(-1), Zn: 1562 microg g(-1)) with an available fraction which is higher than 40% for the Cd and Zn. The abundance of trace elements (free ionic and available forms) in water and sediment presents a durable risk of their transfer to food chains.

Acids↗
PubMed2002

Sulfur and oxygen isotope geochemistry of acid mine drainage--the polymetallic sulfide deposit "himmelfahrt fundgrube" in Freiberg (Germany).

We investigated physical, chemical and isotope (S, O) parameters of sulfate from acid mine drainage from the polymetallic sulfide ore deposit Freiberg (Gennany), which was mined for more than eight hundred years. Two main groups of water were distinguished: 1. Flowing mine water with sulfate concentrations of less than 9,000 mg/l and pH values higher than 3.2, 2. Pore water in weathered low grade ores and pools with sulfate concentrations higher than 9000mg/l and pH values below 3.2. The sulfur and oxygen isotope composition of sulfate from flowing mine waters reflects mixing of sulfate from two sulfur sources: a) atmospheric sulfur from precipitation and b) sulfate formed as a result of sulfide oxidation processes. Sulfur isotope values of mine water sulfate were used to estimate the contribution of sulfate derived through oxidation of sulfides. The sulfur isotope composition of pore water sulfate and precipitated sulfate (jarosite) from weathered low grade ore samples is identical to the sulfur isotope composition of primary sulfides. The oxygen isotope composition of pore water sulfate from low grade ore samples indicates that the oxidation process proceeds relatively slowly in 02-depleted waters, probably without significant microbial catalysis.

Geological Phenomena↗
PubMed2004

Sources and circulation of water and arsenic in the Giant Mine, Yellowknife, NWT, Canada.

Recovery of gold from arsenopyrite-hosted ore in the Giant Mine camp, Yellowknife, NWT, Canada, has left a legacy of arsenic contamination that poses challenges for mine closure planning. Seepage from underground chambers storing some 237,000 tonnes of arsenic trioxide dust, has As concentrations exceeding 4000 ppm. Other potential sources and sinks of As also exist. Sources and movement of water and arsenic are traced using the isotopes of water and sulphate. Mine waters (16 ppm As; AsV/AsIII approximately 150) are a mixture of two principal water sources--locally recharged, low As groundwaters (0.5 ppm As) and Great Slave Lake (GSL; 0.004 ppm As) water, formerly used in ore processing and discharged to the northwest tailings impoundment (NWTP). Mass balance with delta18O shows that recirculation of NWTP water to the underground through faults and unsealed drillholes contributes about 60% of the mine water. Sulphate serves to trace direct infiltration to the As2O3 chambers. Sulphate in local, low As groundwaters (0.3-0.6 ppm As; delta34SSO4 approximately 4% and delta18OSO4 approximately -10%) originates from low-temperature aqueous oxidation of sulphide-rich waste rock. The high As waters gain a component of 18O-enriched sulphate derived from roaster gases (delta18OSO4) = + 3.5%), consistent with their arsenic source from the As2O3 chambers. High arsenic in NWTP water (approximately 8 ppm As; delta18OSO4 = -2%) derived from mine water, is attenuated to close to 1 ppm during infiltration back to the underground, probably by oxidation and sorption by ferrihydrite.

Arsenic↗
PubMed2001

Application of radar to detect pedestrian workers near mining equipment.

Between 1990 and 1996, 133 accidents occurred and 23 mine workers were killed when haulage trucks used in surface mines collided with another smaller vehicle, a mine structure, or a pedestrian worker. These accidents were caused by a lack of visibility from the cab of the truck. Similar accidents are common with other types of equipment, such as front-end loaders and shovels. There are several methods for improving the operator's awareness of objects or people around the equipment including improved mirror designs, video cameras, and sensor technologies. Researchers at the National Institute for Occupational Safety and Health (NIOSH) are evaluating collision warning systems that are based on radar technology. These systems are mounted on the mining equipment to monitor one or more of the blind areas. An alarm is provided to the operator if an object or person enters the radar's detection area. Tests consisted of mounting the systems on a 50-ton-capacity truck typically used in quarries and a 240-ton-capacity truck used at a surface mine. This article summarizes the test procedure and results of evaluations of several off-the-shelf and prototype radar systems. False alarm rates and reliable detection zones for pedestrians were recorded for various mounting configurations on the rear of the trucks. Mounting radar systems on large equipment presents several challenges; however, the technology does show promise for this application.

Accidents, Occupational↗
PubMed2006

Implementation of a best management practice (BMP) system for a clay mining facility in Taiwan.

The present paper describes the planning and implementation of a best management practice (BMP) system for a clay mining facility in Northern Taiwan. It is a challenge to plan and design BMPs for mitigating the impact of clay mining operations due to the fact that clay mining drainage typically contains very high concentrations of suspended solids (SS), Fe-ions, and [H+] concentrations. In the present study, a field monitoring effort was conducted to collect data for runoff quality and quantity from a clay mining area in Northern Taiwan. A BMP system including holding ponds connected in series was designed and implemented and its pollutant removal performance was assessed. The assessment was based on mass balance computations and an analysis of the relationship between BMP design parameters such as pond depth, detention time, surface loading rate, etc. and the pollutant removal efficiency. Field sampling results showed that the surface-loading rate is exponential related to the removing rate. The results provide the basis for a more comprehensive and efficient BMP implementation plan for clay mining operations.

Aluminum Silicates↗
PubMedDate not supplied

Exposure of miners to diesel exhaust particulates in underground nonmetal mines.

A study was initiated to examine worker exposures in seven underground nonmetal mines and to examine the precision of the National Institute for Occupational Safety and Health (NIOSH) 5040 sampling and analytical method for diesel exhaust that has recently been adopted for compliance monitoring by the Mine Safety and Health Administration (MSHA). Approximately 1000 air samples using cyclones were taken on workers and in areas throughout the mines. Results indicated that worker exposures were consistently above the MSHA final limit of 160 micrograms/m3 (time-weighted average; TWA) for total carbon as determined by the NIOSH 5040 method and greater than the proposed American Conference of Governmental Industrial Hygienists TLV limit of 20 micrograms/m3 (TWA) for elemental carbon. A number of difficulties were documented when sampling for diesel exhaust using organic carbon: high and variable blank values from filters, a high variability (+/- 20%) from duplicate punches from the same sampling filter, a consistent positive interference (+26%) when open-faced monitors were sampled side-by-side with cyclones, poor correlation (r 2 = 0.38) to elemental carbon levels, and an interference from limestone that could not be adequately corrected by acid-washing of filters. The sampling and analytical precision (relative standard deviation) was approximately 11% for elemental carbon, 17% for organic carbon, and 11% for total carbon. An hypothesis is presented and supported with data that gaseous organic carbon constituents of diesel exhaust adsorb onto not only the submicron elemental carbon particles found in diesel exhaust, but also mining ore dusts. Such mining dusts are mostly nonrespirable and should not be considered equivalent to submicron diesel particulates in their potential for adverse pulmonary effects. It is recommended that size-selective sampling be employed, rather than open-faced monitoring, when using the NIOSH 5040 method.

Adult↗
PubMedDate not supplied

Comparison of coal mine dust size distributions and calibration standards for crystalline silica analysis.

Since 1982 standard calibration materials recommended for respirable crystalline silica analysis by the Mine Safety and Health Administration (MSHA) P7 Infrared Method and the National Institute for Occupational Safety and Health (NIOSH) X-ray Diffraction (XRD) Analytical Method 7500 have undergone minor changes in size distribution. However, a critical assumption has been made that the crystalline silica in ambient mine atmosphere respirable dust samples has also remained essentially unchanged in particle size distribution. Therefore, this work compared recent particle size distributions of underground coal mine dust and the silica component of these dusts with estimated aerodynamic particle size distributions of calibration standard materials MIN-U-SIL 5, Berkeley 5, and SRM 1878 used by two crystalline silica analysis techniques. Dust impactor sampling data for various locations in 13 underground coal mines were analyzed for the respirable mass median aerodynamic diameters. The data suggest that the MSHA P7 method will underestimate the silica content of the sample by at most 7.4% in the median size range 0.9 to 3.6 microm, and that it is unlikely one would obtain any significant error in the MSHA P7 method analysis when the method uses Berkeley 5, MIN-U-SIL 5, or SRM 1878 as a calibration standard material. The results suggest that the NIOSH Analytical Method 7500 would be more appropriate for a dust sample that is representative of the total (no cyclone classifier) rather than the respirable airborne dust, particularly because the mass fraction in the size range below 4 microm is usually a small percentage of the total airborne dust mass. However, NIOSH Analytical Method 7500 is likely to underestimate the silica content of an airborne respirable dust sample by only 5 to 10%. The results of this study also suggest that any changes that may have occurred in the median respirable size of airborne coal mine dust are not significant enough to cause any appreciable error in the current methods used for respirable crystalline silica analysis.

Coal↗
PubMed2007

Noise exposure and hearing conservation in U.S. coal mines--a surveillance report.

This study examines the patterns and trends in noise exposure documented in data collected by Mine Safety and Health Administration inspectors at U.S. coal mines from 1987 through 2004. During this period, MSHA issued a new regulation on occupational noise exposure that changed the regulatory requirements and enforcement policies. The data were examined to identify potential impacts from these changes. The overall annual median noise dose declined 67% for surface coal mining and 24% for underground coal mining, and the reduction in each group accelerated after promulgation of the new noise rule. However, not all mining occupations experienced a decrease. The exposure reduction was accompanied by an increase of shift length as represented by dosimeter sample duration. For coal miners exposed above the permissible exposure level, use of hearing protection devices increased from 61% to 89% during this period. Participation of miners exposed at or above the action level in hearing conservation programs rapidly reached 86% following the effective date of the noise rule. Based on inspection data, the occupational noise regulation appears to be having a strong positive impact on hearing conservation by reducing exposures and increasing the use of hearing protection devices and medical surveillance. However, the increase in shift duration and resulting reduction in recovery time may mitigate the gains somewhat.

Coal Mining↗
PubMed2004

Distribution characteristics of rare earth elements in children's scalp hair from a rare earths mining area in southern China.

In order to demonstrate the validity of using scalp hair rare earth elements (REEs) content as a biomarker of human REEs exposure, data were collected on REEs exposure levels from children aged 11-15 years old and living in an ion-adsorptive type light REEs (LREEs) mining and surrounding areas in southern China. Sixty scalp hair samples were analyzed by ICP-MS for 16 REEs (La Lu, Y and Sc). Sixteen REEs contents in the samples from the mining area (e.g., range: La: 0.14-6.93 microg/g; Nd: 0.09-5.27 microg/g; Gd: 12.2-645.6ng/g; Lu: 0.2-13.3 ng/g; Y: 0.03-1.27 microg/g; Sc: 0.05-0.30 microg/g) were significantly higher than those from the reference area (range: La: 0.04-0.40 microg/g; Nd: 0.04-0.32 microg/g; Gd: 8.3-64.6 ng/g; Lu: 0.4-3.3ng/g; Y: 0.03-0.29 microg/g; Sc: 0.11-0.36 microg/g) and even much higher than those published in the literature. The distribution pattern of REEs in scalp hair from the mining area was very similar to that of REEs in the mine and the atmosphere shrouding that area. In conclusion, the scalp hair REEs contents may indicate not only quantitatively but also qualitatively (distribution pattern) the absorption of REEs from environmental exposure into human body. The children living in this mining area should be regarded as a high-risk group with REEs (especially LREEs) exposure, and their health status should be examined from a REEs health risk assessment perspective.

Absorption↗
PubMed2004

High radon exposure in a Brazilian underground coal mine.

The main source of radiation exposure in most underground mining operations is radon and radon decay products. The situation of radon exposure in underground mining in Brazil is still unknown, since there has been no national regulation regarding this exposure. A preliminary radiological survey in nonuranium mines in Brazil indicated that an underground coal mine in the south of Brazil had high radon concentration and needed to be better evaluated. This paper intends to present an assessment of radon and radon decay product exposure in the underground environment of this coal mining industry and to estimate the annual exposure to the workers. As a product of this assessment, it was found that average radon concentrations at all sampling campaign and excavation sites were above the action level range for workplaces of 500-1500 Bq m(-3) recommended by the International Commission on Radiological Protection--ICRP 65. The average effective dose estimated for the workers was almost 30 times higher than the world average dose for coal miners.

Air Pollutants, Occupational↗
PubMed2003

Dust exposure during small-scale mining in Tanzania: a pilot study.

Small-scale mining in developing countries is generally labour-intensive and carried out with low levels of mechanization. In the Mererani area in the northern part of Tanzania, there are about 15000 underground miners who are constantly subjected to a poor working environment. Gemstones are found at depths down to 500 m. The objectives of this pilot study were to monitor the exposure to dust during work processes, which are typical of small-scale mining in developing countries, and to make a rough estimation of whether there is a risk of chronic pulmonary diseases for the workers. Personal sampling of respirable dust (n = 15) and 'total' dust (n = 5) was carried out during three consecutive days in one mine, which had a total of 50 workers in two shifts. Sampling started immediately before the miners entered the shaft, and lasted until they reappeared at the mine entrance after 5-8 h. The median crystalline silica content and the combustible content of the respirable dust samples were 14.2 and 5.5%, respectively. When drilling, blasting and shovelling were carried out, the exposure measurements showed high median levels of respirable dust (15.5 mg/m(3)), respirable crystalline silica (2.4 mg/m(3)), respirable combustible dust (1.5 mg/m(3)) and 'total' dust (28.4 mg/m(3)). When only shovelling and loading of sacks took place, the median exposures to respirable dust and respirable crystalline silica were 4.3 and 1.1 mg/m(3). This study shows that the exposure to respirable crystalline silica was high during underground small-scale mining. In the absence of personal protective equipment, the miners in the Mererani area are presumably at a high risk of developing chronic silicosis.

Adult↗
PubMed1977

Cancer in asbestos-mining and other areas of Quebec.

Employing incidence data from the Quebec Tumor Registry, we examined the relative risks of cancer of all sites for the years 1969-73 in the asbestos-mining, rural, and metropolitan counties of Quebec Province, Canada. Generally, rates for males exceeded those for females, and the relative risks in the asbestos-mining counties for 7-10 different sites of cancer, all of low incidence, were from 1.50 to 8.08 times those of other rural counties of the Province for both sexes. Metropolitan counties exhibited equally high risk for many of these sites. We discovered higher risks among males in asbestos-mining counties for cancer of the pleura, peritoneum, lip, tongue, salivary gland, mouth, and small intestine and higher risks among females for cancer of the pleura, lip, kidney, salivary gland, and for melanoma. Because of the likelihood of a long latent period for asbestos-related cancers, the risks we observed were possibly the product of since-altered occupational and environmental conditions existing 20-30 years ago in the asbestos-mining areas. The similarities in risks for most cancers in asbestos-mining and urban areas were noteworthy.

Asbestos↗
PubMed2001

Radon progeny in Egyptian underground phosphate mines.

In addition to the workers in uranium mines, the staff of other underground mines, such as workers in underground phosphate mines, can be exposed to 222Rn and its progeny. In this study the individual radon progeny concentrations were measured in three Egyptian underground phosphate mines to estimate the occupational exposure of the workers at those sites. A filter method was used to measure individual radon progeny concentrations (218Po, 214Pb and 214Po). The reported mean values of radon progeny concentrations exceed the action levels which are recommended by ICRP 65 (1993). Based on the measured individual radon progeny concentrations (218Po, 214Pb and 214Po) in these mines, the annual effective dose for the workers has been calculated using the lung dose model of ICRP 66 (1994). According to the obtained results, some countermeasures were recommended in this study to minimise these exposure levels.

Air Pollutants, Radioactive↗
PubMed2001

Fatal carbon monoxide poisoning after the detonation of explosives in an underground mine: a case report.

An unusual death caused by carbon monoxide poisoning after the detonation of explosives in an underground mine was investigated by the Office of the Medical Investigator of the State of New Mexico. The 50-year-old miner had 18 years of mining experience but no documented safety training. He collapsed approximately 20 minutes after entering the mine and working at the bottom of the single vertical shaft. The tight confines of the mine shaft hindered rescue personnel from reaching him, and the body was not recovered until 2 days later. The autopsy showed severe coronary artery atherosclerosis with remote and resolving myocardial microinfarcts, as well as the characteristic pink lividity of carbon monoxide poisoning, which was confirmed by laboratory analysis. Detailed investigation of the scene revealed no sources of carbon monoxide other than the explosives. The case represents an uncommon cause of death in mining that may have been avoided through the use of proper safety procedures, and illustrates the importance of recognizing the many sources of carbon monoxide.

Carbon Monoxide Poisoning↗